Bridging is a lesson for individuals in a school to catch up but is often considered as a "DOS" in which you can play games on the computer.
Mentioning of the subject Bridging will usually be greeted with a cry of WHEY! from all persons nearby.

Apparently 4 GCSE's can be obtained from this dos lesson.

Michael: You in Bridging next, Jonny?
(Greeted by a cry of WHEY! from all nearby persons)
Jonny: Yeah, it's a dos, I might just Chong the Bhudda and play games whilst achieving 4 A*

To have gained a rapport with a person of the desired sex only to have it quashed by saying something that is ridiculous or overly 'nerdy' you kill the conversation.

Origins of this terminology date back to an occurrence on a New Zealand Contiki tourist bus in which a man was talking to a woman in a way some would call light flirting. All was going well until he started going on some tangent about how the Auckland bridge's original designs had etc etc. Hence killing the conversation. It is from here we take our term Bridging.